EFFECT OF VARYING STRENGTH AND ORIENTATION OF LOCAL INTERSTELLAR MAGNETIC-FIELD ON CONFIGURATION OF EXTERIOR HELIOSPHERE - 3D MHD SIMULATIONS

The aim of this paper is to present the effects of varying magnitude a nd orientation of the local interstellar magnetic field on the heliosp heric boundary region (the region between the termination shock and th e bow shock containing the heliopause). Other effects such as interste llar neutrals, cosmic rays and the asymmetry of the solar wind caused by its heliolatitude dependence are disregarded. We calculate the shap e and structure of the heliospheric boundary region for different inte rstellar Alfvenic Mach numbers and various inclination angles between Very Local InterStellar Medium (VLISM) velocity and magnetic field vec tors using a fully three-dimensional MHD computational analysis. The n ew results show the asymmetry of this region for inclination angles 0 degrees < alpha < 90 degrees and are in agreement with the Newtonian a pproximation theory (Fahr et al. 1986, 1988) concerning trends in the heliopause orientation and location. Unlike the NA model which only qu alitatively indicates the effects of the VLISM magnetic field on the h eliospheric boundary region the present 3D MHD calculations reveal ful ly the nature of these effects by capturing all discontinuities includ ing the termination shock, heliopause and bow shock. The numerical sch eme employed in this study is fully implicit and conservative, using a Poe-type Riemann solver in a generalized coordinate system.